"If you get fired for not being in the office 5x8"
That was always the policy during my 28 years there. While there may have been temporary arrangements due to the pandemic, this doesn't confer on anyone permanent new rights.
What you'll see in writing is warnings, then a final warning, and you'll be dismissed for cause. The only exception I see is, if one was hired before the pandemic as virtual, then I can see a separation for cause attributable to the employer.
It has always been clear that the virtual office for those formerly at work in the office was for pandemic related reasons. Rots of ruck trying to claim otherwise.